How much electricity do 100 Christmas lights use?

The amount of electricity 100 Christmas lights use depends on the type of bulbs you're using (LED, incandescent, or other variations), the wattage of each bulb, and how long the lights are turned on. Here’s a breakdown of how to calculate electricity usage for different types of lights:

1. LED Christmas Lights:

LED lights are the most energy-efficient option and use far less electricity than incandescent lights.

• Average wattage per LED bulb: About 0.05 watts (5 milliwatts)

• 100 LED lights:
  $100 \times 0.05 \, \text{watts} = 5 \, \text{watts}$

  • Hourly electricity use: 5 watts
  • Annual electricity consumption (assuming lights are on for 5 hours a day for 30 days in December): $5 \, \text{watts} \times 5 \, \text{hours} = 25 \, \text{watt-hours per day}$ $25 \, \text{watt-hours per day} \times 30 \, \text{days} = 750 \, \text{watt-hours}$ $750 \, \text{watt-hours} \div 1000 = 0.75 \, \text{kWh}$

So, 100 LED Christmas lights would use about 0.75 kWh of electricity over the course of 30 days if they're on for 5 hours a day.

2. Incandescent Christmas Lights:

Incandescent bulbs use significantly more energy compared to LEDs.

• Average wattage per incandescent bulb: About 0.5 watts

• 100 incandescent lights: $100 \times 0.5 \, \text{watts} = 50 \, \text{watts}$

  • Hourly electricity use: 50 watts
  • Annual electricity consumption (assuming lights are on for 5 hours a day for 30 days in December): $50 \, \text{watts} \times 5 \, \text{hours} = 250 \, \text{watt-hours per day}$ $250 \, \text{watt-hours per day} \times 30 \, \text{days} = 7500 \, \text{watt-hours}$ $7500 \, \text{watt-hours} \div 1000 = 7.5 \, \text{kWh}$

So, 100 incandescent Christmas lights would use about 7.5 kWh of electricity over the course of 30 days if they're on for 5 hours a day.

3. Cost Calculation:

To calculate the cost of running your Christmas lights, multiply the total kWh by the rate your electricity provider charges per kilowatt-hour (kWh). For example, in the UK, the average cost per kWh is approximately £0.30.

• For 100 LED lights:
  $0.75 \, \text{kWh} \times 0.30 = £0.23$ for 30 days
• For 100 incandescent lights:
  $7.5 \, \text{kWh} \times 0.30 = £2.25$ for 30 days

Conclusion:

• LED lights are very cost-effective, using only about £0.23 for a month (if left on for 5 hours a day).
• Incandescent lights are much more expensive, costing £2.25 for the same period.

Final Tip:

Switching to LED Christmas lights can significantly reduce your electricity consumption and save you money in the long run.